Commit b8904164 authored by Peter Maydell's avatar Peter Maydell
Browse files

Merge remote-tracking branch 'remotes/armbru/tags/pull-monitor-2018-07-31' into staging 



Monitor patches for 2018-07-31 (3.0.0-rc3)

# gpg: Signature made Tue 31 Jul 2018 16:46:16 BST
# gpg:                using RSA key 3870B400EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>"
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>"
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-monitor-2018-07-31:
  monitor: temporary fix for dead-lock on event recursion

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parents 42e76456 9a105406

monitor.c

+43 −1
Original line number Diff line number Diff line
@@ -633,7 +633,7 @@ static void monitor_qapi_event_handler(void *opaque); 
 * applying any rate limiting if required.

 */

static void

monitor_qapi_event_queue(QAPIEvent event, QDict *qdict, Error **errp)

monitor_qapi_event_queue_no_reenter(QAPIEvent event, QDict *qdict)

{

    MonitorQAPIEventConf *evconf;

    MonitorQAPIEventState *evstate;
@@ -688,6 +688,48 @@ monitor_qapi_event_queue(QAPIEvent event, QDict *qdict, Error **errp) 
    qemu_mutex_unlock(&monitor_lock);

}



static void

monitor_qapi_event_queue(QAPIEvent event, QDict *qdict, Error **errp)

{

    /*

     * monitor_qapi_event_queue_no_reenter() is not reentrant: it

     * would deadlock on monitor_lock.  Work around by queueing

     * events in thread-local storage.

     * TODO: remove this, make it re-enter safe.

     */

    typedef struct MonitorQapiEvent {

        QAPIEvent event;

        QDict *qdict;

        QSIMPLEQ_ENTRY(MonitorQapiEvent) entry;

    } MonitorQapiEvent;

    static __thread QSIMPLEQ_HEAD(, MonitorQapiEvent) event_queue;

    static __thread bool reentered;

    MonitorQapiEvent *ev;



    if (!reentered) {

        QSIMPLEQ_INIT(&event_queue);

    }



    ev = g_new(MonitorQapiEvent, 1);

    ev->qdict = qobject_ref(qdict);

    ev->event = event;

    QSIMPLEQ_INSERT_TAIL(&event_queue, ev, entry);

    if (reentered) {

        return;

    }



    reentered = true;



    while ((ev = QSIMPLEQ_FIRST(&event_queue)) != NULL) {

        QSIMPLEQ_REMOVE_HEAD(&event_queue, entry);

        monitor_qapi_event_queue_no_reenter(ev->event, ev->qdict);

        qobject_unref(ev->qdict);

        g_free(ev);

    }



    reentered = false;

}



/*

 * This function runs evconf->rate ns after sending a throttled

 * event.